Connector for semi-rigid coaxial cable



Jan. 14, 1964 A. B. CARVER coNNEcToR Foa SEMI-RIGID coAxIAL CABLE Filed Nov. 14, 1961` AUGUST a. CARVER INVENTOR A''TORNEYS E .N .0i g

United States Patent Gilice 3,117,357 Patented Jan. 14, 1964 3,117,357 CNNECTUR FOR SEMll-RGED CAXKAL CABLE August lil. Carver, Wheaton, Md., assigner to the United States of America as represented by the Secretary ot the Navy Filed Nov. 14, 1961, Ser. No. 152,367 6 Claims. (Cl. 24-126) The invention described herein, if patented, may be manufactured and used -by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates generally to electrical connectors, and more particularly to an improved connector for semirigid coaxial conductors and the like.

It is often necessary to couple semi-rigid coaxial conductors or conduits to other conduits, to intermediate connectors, or to a fixed socket. Because the material from which the conduits are made is usually relatively soft and of limited structural strength, it is often ditlcult to make a joint which will meet minimum strength standards while not causing structural damage to the conduit. Conduit connections often must be made in large numbers while in the field, and the personnel whose duty it is to produce the joints are frequently not skilled mechanics. Accordingly, it is highly desirable to provide a connector that can be readily made-up under field conditions, the quality of which is substantially independent of the skill of the operator.

lt is, therefore, the principal object of this invention to provide a connector for semi-rigid coaxial conduit, so constructed that the quality of the connection is predetermined and is substantially independent of the skill of the assembler.

Another object of the present invention is to provide a connector for semi-rigid coaxial conductors, so constructed as to permit assembly without structural damage to the conduit.

Further objects of the invention are to provide a connector that is inexpensive and that is easily assembled.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. l is a perspective of one end of a coaxial conduit joint assembly employing the connector of the invention;

FIG. 2 is a section of the joint assembly of FIG. 1, showing the construction thereof;

FIG. 3 is an end elevation of a coaxial conduit with a securing sleeve and a screw thimble mounted therein; and

FIG. 4 is a perspective showing `a coaxial conduit, a securing sleeve, a flange-bearing connector sleeve, and a screw thimble in pre-assembled positions.

It is common practice to connect a semi-rigid conduit or tube to another similar element by first mounting a flange-bearing connector sleeve on the end of the tube. An annular member, such as a screw thimble, is then employed to engage the rear side of the flange on the sleeve, the annular member Vbeing secured to the other element to thereby couple the tube in position. The present invention is directed primarily to an improved structure for securing a connector sleeve to a conduit.

In the invention a flange-bearing connector sleeve is secured to the end of a semi-rigid coaxial conduit by means of a longitudinally-split securing sleeve. The split sleeve is cylindrical throughout the majority of its length and contains serrations on its inner surface. The rear end portion of the outer surface thereof is conically tapered downwardly from the cylindrical portion of said surface toward the rear edge of the sleeve. The connector sleeve contains a cylindrical recess of a size to contain the split securing sleeve when it is in a compressed state, 'with the serrations on the inner surface of the latter biting into the outer surface of the tube. The connector is assembled to the tube by rst positioning the securing sleeve on the tube and then pressing the connector sleeve into position, the tapering surface of the former functioning to aid in the assembly.

Referring now to the drawings, a pair of semi-rigid coaxial conduits 2 are shown in FIG. 2 to be coupled by a connector tube 4. Each conduit 2 includes a cylindrical tube 6, a conductor concentrically disposed within the tube and projecting from one end thereof, and spirally wound insulation iti which also serves to properly center the conductor S. Attached to each conduit 2 is a cylindrical connector sleeve 12, the forward end 14 of said sleeve being enlarged. A radial face 16 extends between a central reduced diameter portion 18 of the connector sleeve and the outer surface of the enlarged portion 14.

T he connector tube 4 contains a through passageway 2G, and has an annular recess 22 in each end thereof of a size to receive the connector sleeve-bearing end of one of the conduits 2. Disposed concentrically within passageway Ztl is a connecting tube 24 of a size to telescopically receive the projecting conductors 8, said tube 24 being positioned within passageway Ztl by insulation 26. The external ends of connector tube 4 are both somewhat reduced in diameter, and have threads thereon.

The conduits if; are secured to the connector tube 4 by screw thimbles 2% which are threaded on the opposite ends of said tube, the thimbles being slidably received on the reduced diameter portions 1S of the connector sleeves 12 and having ilange portions 32 which abut the faces 16.

Each connector sleeve l2 is secured to a conduit 2 by interaction with a securing sleeve 34. Each sleeve 34, as best seen in PEG, 4, is cylindrical in form and has a split 36 extending the full length thereof. The interior of the sleeve has annular serrations 38 thereon, and the external surface thereof consists of a cylindrical front portion 4t) and an axially inwardly tapering rear portion 42, the cylindrical portion extending for a substantial proportion of the sleeves length. When the sleeve is in the preassernbled condition shown in FlG. 4 the inner diameter thereof is such that the serrations 38 just engage the outer cylindrical surface of the conduit 2.

rEhe tube 6 which forms the outer member of conduit 2 is normally of a soft, conductive material such as copper or aluminum, and accordingly the compressive stress to which it can be subjected before structural failure is quite limited. The securing sleeve 34 is constructed of a harder material than tube 6, such as brass. Thus, when the split securing sleeve is compressed the serrations 38 bite into the softer surface of tube 6. If the tube is not to be collapsed the degree to which the split sleeve is compressed must lbe controlled. However, in order for the serrations 4to obtain a hrm grip upon the tube the sleeve must be compressed at least a certain minimum amount. lf uniformity is to be obtained through a great number of joints with a minimum of operator skill a means for automatically determining the degree to which the split sleeve is to be compressed is highly desirable. The present invention produces this desired result.

The connector sleeve 12 has a cylindrical bore 44 extending completely therethrough, the forward end of which is enlarged to form a cylindrical recess 46 of an axial length identical to the length of the securing sleeve 34. The recess 46 terminates at its rear end in a radial face 4d, and the diameter of the recess is so chosen that when the securing sleeve 34 is disposed therein (FIG. 2), the latter is properly compressed about tube 6, with the serrations 38 biting into the surface of the tube to the desired extent. The portion of the bore 44 to the rear of recess 46 is of a diameter just slightly larger than the outer diameter of the tube 6.

To assemble the connector sleeve to the conduit 2 the elements are iirst arranged about the tube 6 as shown in FIG. 4, Iwith the securing sleeve 34 in front of the connector sleeve 12 and with the tapered surface 42 facing the recess 46. The elements are then placed in a suitable press and the connector sleeve 12 is lforced over the split securing sleeve. The tapered surface d2 engages the forward edge of the wall defining recess 46, thereby causing the securing sleeve to be compressed about the tube. When the securing sleeve has been reduced sufficiently in diameter to permit the cylindrical portion 40 thereof to telescope into recess 46 compressive forces cease to be applied, and the sleeve enters the recess until the rear face thereof abuts face 48 and the sleeve is completely contained therein. Assembly isl then completed, the elements Abeing secured in position by the frictional contact between the mating cylindrical surfaces of the two sleeves.

By properly dimensioning the recess 46 and the securing sleeve 34 relative to tube 6 is is readily seen that the compressive forces acting to secure the conduit 2 in position may be predetermined, and that they will be constant from joint to joint (provided manufacturing tolerances are maintained accurately) almost without regard to the skill of the assembler. Thus, the invention provides a reliable, easily made-up, uniform quality connecting structure particularly suitable for iield installation.

Obviously, many modications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a connector for semi-rigid coaxial conduit, said conduit including an outer cylindrical tube of relatively soft metal; a longitudinally-split cylindrical securing sleeve of relatively hard metal disposed about said tube, said securing sleeve having serrations on its inner surface and having an axially inwardly tapered end portion, and a connector sleeve disposed about said securing sleeve and said tube, said connector sleeve having a cylindrical recess therein for receiving said securing sleeve in a ixed longitudinal relationship with said connector sleeve, the diameter of said recess being such that when said securing sleeve is disposed therein it will be compressed to a predetermined degree about said tube with said serrations biting into said -tube to a predetermined extent.

2. The combination as recited in claim 1, wherein said securing sleeve includes an external cylindrical portion forwardly of said tapered portion, said external cylindrical portion being of a length at last as great as said tapered portion and having a constant diameter throughout.

3. A connector for coupling a semi-rigid coaxial conduit to a member having a socket therein, said conduit including an outer cylindrical tube of relatively soft metal; comprising a longitudinally-split cylindrical securing sleeve of relatively hard metal disposed about an end of said tube, said securing sleeve having serrations on its inner surface and having an axially inwardly tapered rear end portion," a connector sleeve disposed about said securing sleeve and said tube and receivable Iwithin said socket, said connector sleeve having a cylindrical recess therein for receiving said securing sleeve in a xed longitudinal relationship with said connector, the diameter of said recess being such that when said securing sleeve is disposed therein it will be compressed to a predetermined degree about said tube with said serrations biting into said tube to a predetermined extent, and means engageable with said connector sleeve and said member for securing said connector sleeve within said socket.

4. A connector as recited in claim 3, wherein said securing sleeve has an external cylindrical portion of uniform diameter throughout extending forwardly from said tapered portion, said cylindrical portion being of substantial length and being engageable with the cylindrical wall of said recess whereby to frictionally secure together said securing sleeve and said connector sleeve.

5. A connector as recited in claim 3, wherein said member is threaded externally about said socket, said connector sleeve has an abutment shoulder spaced rnedially thereof, and including a screw thimble engageable with said threaded portion of said member and said abutment shoulder of said connector sleeve.

6. In a device for splicing semi-rigid coaxial conduits, said conduits including outer cylindrical tubes of relatively soft metal and internal conducting portions, a cylindricalconnector element having an internal receptacle disposed within its central portion for receiving said conducting portions and providing an electrical contact therebetween and including internal sockets disposed outwardly of said receptacle, and external threaded portions adjacent each end, a pair of longitudinally-split securing sleeves of relatively hard metal each having an external cylindrical portion of uniform diameter, an axially inwardly tapered end portion and serrations on its inner surface disposed about the ends of said tubes, a pair of connector sleeves disposed about said securing sleeves and said tubes and receivable within said sockets, said connector sleeves having cylindrical recesses therein for receiving said securing sleeves in a fixed longitudinal relationship, the diameter of each of said recesses being such that when said securing sleeves are disposed therein they will be deformed to a predetermined value of compression about said tubes with said serrations gripping said tubes, and a pair of thimble screws engaging said cylindrical connector element for securing said connector sleeves within said sockets.

References Cited in the tile of this patent UNITED STATES PATENTS 1,646,660 Prince Oct. 25, 1927 1,710,416 Goeller Apr. 23, 1929 1,793,455 Buchanan Feb. 24, 1931 2,131,987 Studt et al Oct. 4, 1938 2,210,058 Blackburn Aug. 6, 1940 2,228,685' Benjamin Jan. 14, 1941 2,449,983 Devol Sept. 28, 1948 3,010,747 Bondon Nov. 28, 1961 3,040,405 Solum June 26, 1962 FOREIGN PATENTS 829,590 France Apr. 5, 1938 

1. IN A CONNECTOR FOR SMEI-RIGID COAXIAL CONDUIT, SAID CONDUIT INCLUDING AN OUTER CYLINDRICAL TUBE OF RELATIVELY SOFT METAL; A LONGITUDINALLY-SPLIT CYLINDRICAL SECURING SLEEVE OF RELATIVELY HARD METAL DISPOSED ABOUT SAID TUBE, SAID SECURING SLEEVE HAVING SERRATIONS ON ITS INNER SURFACE AND HAVING AN AXIALLY INWARDLY TAPERED END PORTION, AND A CONNECTOR SLEEVE DISPOSED ABOUT SAID SECURING SLEEVE AND SAID TUBE, SAID CONNECTOR SLEEVE HAVING A CYLINDRICAL RECESS THEREIN FOR RECEIVING SAID SECURING SLEEVE IN A FIXED LONGITUDINAL RELATIONSHIP WITH SAID CONNECTOR SLEEVE, THE DIAMETER OF SAID RECESS BEING SUCH THAT WHEN SAID SECURING SLEEVE IS DISPOSED THEREIN IT WILL BE COMPRESSED TO A PREDETERMINED DEGREE ABOUT SAID TUBE WITH SAID SERRARTIONS BITING INTO SAID TUBE TO A PREDETERMINED EXTEND. 